The majority of bagel-begun-3-setters are close in the 2nd set - 71% of the matches have a score of 6-3(+) in the 2nd set.
...but that number goes down in the 3rd set; 61% of the matches have a score of 6-3(+) in the 2nd set.

May I throw this one in? Wendy Turnbull defeating Rosie Casals: 0-6 6-2 6-3 in the 1979 Avon Of Philadelphia Semi-Finals? Also, as a sidebar Virginia Wade def Sue Barker in the other semi: 1-6 7-5 6-3.